/*
 * MIT License
 *
 * Copyright (c) 2023 北京凯特伟业科技有限公司
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.je.bpm.engine.impl.util.io;

import com.je.bpm.engine.ActivitiException;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;


public class InputStreamSource implements StreamSource {

    // This class is used for bpmn parsing.
    // The bpmn parsers needs to go over the stream at least twice:
    // Once for the schema validation and once for the parsing itself.
    // So we keep the content of the inputstream in memory so we can
    // re-read it.

    protected BufferedInputStream inputStream;
    protected byte[] bytes;

    public InputStreamSource(InputStream inputStream) {
        this.inputStream = new BufferedInputStream(inputStream);
    }

    @Override
    public InputStream getInputStream() {
        if (bytes == null) {
            try {
                bytes = getBytesFromInputStream(inputStream);
            } catch (IOException e) {
                throw new ActivitiException("Could not read from inputstream", e);
            }
        }
        return new BufferedInputStream(new ByteArrayInputStream(bytes));
    }

    @Override
    public String toString() {
        return "InputStream";
    }

    public byte[] getBytesFromInputStream(InputStream inStream) throws IOException {
        long length = inStream.available();
        byte[] bytes = new byte[(int) length];

        int offset = 0;
        int numRead = 0;
        while (offset < bytes.length && (numRead = inStream.read(bytes, offset, bytes.length - offset)) >= 0) {
            offset += numRead;
        }

        if (offset < bytes.length) {
            throw new ActivitiException("Could not completely read inputstream ");
        }

        // Close the input stream and return bytes
        inStream.close();
        return bytes;
    }

}
